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1139Re: 680b Project Update

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  • Steve
    Mar 1, 2007
    • 0 Attachment
      Bill,

      Attachments such as your picture(s) are sent to members who have
      chosen to read these messages via email. However, they don't "stick"
      to the messages that are archived and read online, unless you jump
      through some hoops when posting. As a result, we online readers
      won't see your images.

      It's easier to park your pictures somewhere else and provide us with
      a link. If you don't have your own website for picture storage, I
      have found that Image Shack ( http://imageshack.us/ ) does a good job
      for free. Just store your pix there (up to 1.5MB/picture), then give
      us the URLs for them.

      MITS used a lot of those one-shot ICs. If you have the 8800 floppy
      disk controller boards (8" or 5") or an 8800 or 8800a front panel,
      you'll find several there. If you don't mind cannibalizing them, that
      is.

      Steve
      ============================
      --- In altaircomputerclub@yahoogroups.com, "billdeg" <billdeg@...>
      wrote:
      >
      > Here are my latest 680b restoration project notes.
      >
      > 1) Steve Shepard sent me an ACIA monitor prom which seems to be
      > working. I toggled through the first 26 or so address bits and the
      > data matched the prom code. No monitor dot prompt however.
      Checked
      > using two terminals and hyperterminal/laptop.
      >
      > 2) Also with help from Steve Shepard, learned that the IC in
      position
      > L, 74L123 is missing. I located the position in the schematic to
      > match/confirm. Steve suggested that I review every chip and
      > connection to be sure nothing else is missing/incorrect. I am in
      the
      > process of doing this now. I assumed that the missing IC was
      supposed
      > to be that way, my mistake!
      >
      > 3) I have taken hi-res photos to aid in the analysis. I have
      posted
      > the new pics at the *bottom* of this page, if anyone is
      interested. I
      > also have a link to some of the manuals.
      > www.vintagecomputer.net/MITS/680/pictures.html
      >
      > 4) I checked my chips on hand, I do not have a spare 74L123. If
      > anyone here has one for sale, please let me know. I found a site
      that
      > may be able to help, but I have not called them.
      > http://www.mel.wisc.edu/mel_sale.htm
      >
      > Summary - Given (A big assumption) that all of the soldering is OK,
      I
      > hope that installing a 74L123 in IC L will get me to a dot prompt
      > finally. You can see from the pictures that this is definitely a
      kit,
      > and that some connections were changed at some point.
      >
      >
      > That's all..off to work!
      > Bill D
      >
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